1. Field of the Invention
The present invention relates to a light source device for a photographic color enlarger and more particularly, to a light-diffusing and color-additive type color enlarger which employs a plurality of linear light sources such as Xenon discharge tubes and which emits red, green and blue lights either sequentially or simultaneously from different light sources, the emitted light being a film to be enlarged via a diffusing plate.
2. Description of the Prior Art
A light source such as the Xenon tube has various advantages in that a small-sized body can emit high-brightness light and that the light source virtually generates no heat and requires no cooling device such as a radiator or cooling-fan, and accordingly the entire light source device including the light source can be made small in size. The assignee of the present application has proposed a light source device for a color enlarger which makes the most of this advantage and employs three flash discharge tubes consisting of Xenon tubes. In the devices, the three Xenon tubes serve as red, green and blue color light sources respectively. The device was designed to provide a required exposure amount and color balance by controlling the number of light emissions of each of the three Xenon tubes and the amount of light to be emitted at each time (hereinafter called the unit amount of light emission). The device is disclosed in a U.S. patent application Ser. No. 527,515 filed on Aug. 9, 1983 and assigned to the same assignee as that of this application.
However, this device was designed such that, to provide a uniform color distribution, each of the three Xenon tubes is spaced from the diffusing plate which serves as a plane light source and that, the light passing through the diffusing plate is led to the original film after being reflected once. Accordingly, the light will be considerably reduced before reaching the film, so that a longer exposure time is required. The reduced light also makes difficult the observation of the image on the easel plane and the focus adjustment when viewing the image. The space between the light sources and the diffusing plate as well as the provision of the reflecting means also mitigates against the compactness of the device.